At least 50 people, including five policemen and a journalist, were injured yesterday in a clash between ruling party backed road transport workers and law enforcers over operation of a mobile court of environment directorate task force.

During the unrest, traffic on Barisal-Dhaka highway came to a halt for four hours between 12:30pm and 4:30pm.

A helicopter shifted police constables Mizanur Rahman and Nannu Mia to Combined Military Hospital in Dhaka as their condition deteriorated, police said.

Police detained at least 30 transport workers, pedestrians and passengers from the spot.

Witnesses said the mobile court, supported by Rapid Action Battalion, started to check fitness, detect hydraulic horn, black smoke spewing vehicles in front of Kashipur High School on Barisal-Dhaka highway around 11:30am,.

The court fined seven buses Tk 5,000 each and sentenced five drivers to one month's imprisonment, including a fine of Tk 1000 each. Md Qamaruzzaman, executive magistrate of environment directorate led the drive, said a press release of the directorate.

The court went into operation without any prior notice, claimed Aftab Hossain, president of city Shramik League and road transport workers' union.

It also physically assaulted transport workers and leaders who failed to pay the fine or protested its action, he added.

According to the workers, the situation worsened after the law enforcers assaulted Shah Alam, secretary of the workers' union.

Incensed, they assembled at Nathullabad central bus terminal, about a kilometre away from the mobile court spot and blocked the highway around 12:30pm.

The agitated workers attacked a police pickup while it was crossing the terminal area around 1:15 pm, witnesses said.

Six policemen were riding the van on their return trip from a protocol duty of ruling party whip ASM Firoj.

A strong contingent of riot police rushed to the spot and controlled the situation charging baton and lobbing huge number of tear gas shells around 2:30pm.